A device or element capable of detecting two-dimensional position information is fully used for various devices including a user interface such as a touch panel and an image information acquiring device such as a sensor or a camera, and is considered to be more important as an interface between cyberspace and real space in Cloud Society in the future.
For example, many types of touch panels, such as a resistive film type, a capacitance type, and an infrared type, are proposed and actually demonstrated.
In the resistive film type, an upper conductive film and a lower conductive film are disposed closely to each other, and the panel stands by under a state where a bias voltage is applied to one of the conductive films. Here, when a touch pressure is applied from the outside, the upper conductive film and the lower conductive film are brought into contact with each other to be conductive at the touched point. Therefore, by measuring a potential at the point, the coordinates can be determined.
In the capacitance type, the panel stands by under a state where a drive voltage is appropriately applied to an electrode or a conductive film disposed on the panel. Here, when the panel is touched by a finger or the like, a variation of capacitance is caused. Therefore, by reading a voltage variation due to the capacitance variation at multiple points, the touched point can be detected.
In the infrared type, the panel stands by under a state where infrared light emitting elements (LEDs) are disposed in an array on one end of the panel, and infrared light receiving elements (photo transistors) are disposed in an array on the other end of the panel, so as to continuously scan with an infrared ray. Here, when a finger or the like approaches from the outside, the infrared ray is interrupted so that a photo transistor at a corresponding position is turned off. Thus, the touched point can be detected.
Patent Literature 1 and Patent Literature 2 disclose a heat/spin current conversion element and a spintronics device, which are basic devices utilizing the spin Seebeck effect that is also utilized in this invention as described later.
In addition, Patent Literature 3 discloses an example of a resistive film type touch panel. In addition, Non Patent Literature 1 discloses the theory of the spin Seebeck effect.
However, the touch panel type such as the resistive film type, the capacitance type, or the infrared type needs an external power supply for applying a bias voltage to detect a position or for probe drive means such as optical scan, and hence standby power is increased. Therefore, the usage is limited if the power supply is difficult. Even if a battery is used, maintenance and management burden such as exchange of the battery is inevitable. It is desired to provide position detection means that does not require a power supply or includes an effective power generation function for a future sensor network, a ubiquitous terminal or the like, which is expected to be used indoors and outdoors in various use scenes.